JP2020175658A - Microwave and electromagnetic heated foaming method, mold and foaming material therefor - Google Patents

Abstract

To provide a microwave and electromagnetic heated foaming method, and a mold and a foaming material therefor.SOLUTION: There is provided a foaming method that comprises: a step of adding a foam material into a mold; a step of simultaneously applying a microwave and electromagnetic energy to the mold under a normal or low pressure; and a step of molding the foam material into molded foam body by the microwave and electromagnetic energy. The mold has a microwave penetrating part and an electromagnetic heating part, which can form a closed receiving space in the mold by screwing the surfaces facing each other. A microwave is applied to the microwave penetrating part, and electromagnetic energy is applied to the electromagnetic heating part. Use of electromagnetic heating achieves: superior thermal conversion efficiency and heating rates to those of ordinary infrared heating or heating with an electric heating tube; energy saving; and foaming under normal pressure or reduced pressure.SELECTED DRAWING: Figure 1

Description

The present invention relates to a foam molding method and a mold and a foam material used therein, and more particularly to a foam molding method by microwave and dielectric heating, and a mold and a foam material used therein.

In the existing foaming method, foam molding is performed by foaming a foaming agent in a foaming material by heat conduction of an external heat source, but since heat is conducted from the outside to the inside of the material, heating tends to be uneven, and the foaming material Quality control is difficult. Such a method of heating by heat conduction of an external heat source usually has to foam in a high pressure environment. However, in the case of a crystalline material that is not applied to high-pressure foaming, problems such as foam breakage or poor moldability are likely to occur.

With the development of science and technology, a method of heating by microwave and foaming has been developed as a foaming method. By resonating and vibrating specific molecules dispersed in the material by microwaves, it is possible to solve the conventional problem of non-uniform heat conduction from the outside to the inside. However, in the microwave heating method, for example, the mold must be made of a plastic material having microwave transparency. However, all-plastic molds have the problem of insufficient durability.

In order to solve the drawbacks of the existing foam molding method and the microwave heating technique derived thereto, the present invention provides a microwave dielectric heating type foam molding method. The microwave dielectric heating type foam molding method of the present invention includes a step of putting a foam material into a mold, a step of simultaneously applying microwave and electromagnetic energy to the mold under normal pressure or reduced pressure environment, and the microwave and the said. It has a step of molding the foam material into a foam molded product by electromagnetic energy. The mold has a microwave transmitting portion and a dielectric heating portion capable of forming a closed receiving space in the mold by screwing surfaces facing each other. Further, the microwave is applied to the microwave transmitting portion, and the electromagnetic energy is applied to the dielectric heating portion.

The foaming material is in an unfoamed, semi-foamed or foamed state when placed in the mold. The foamed state of the foam material is bead-shaped, plate-shaped, strip-shaped, star-shaped, or irregularly shaped. The non-foamed state of the foaming material has a continuously foamed structure, and the foamed or semi-foamed state has a discontinuous foamed structure.

By applying the microwave and the electromagnetic energy to the microwave transmitting portion of the mold and further applying a pneumatic, electric or hydraulic mechanical external force, the microwave transmitting portion is heated by the dielectric heating unit. Tightly fit to.

The present invention also provides a mold applied to the microwave dielectric heating foam molding method. The mold of the present invention has a microwave transmitting portion having a bottom projecting outward and a dielectric heating portion having a top recessed inward and capable of forming a receiving space by screwing with the microwave transmitting portion.

The mold is further provided with an inner lid which is provided between the microwave transmitting portion and the dielectric heating portion, has a bottom portion protruding outward, and can be screwed with the top portion of the dielectric heating portion to form the receiving space.

The microwave heating unit is made of plastic, and the dielectric heating unit is made of metal.

It has a screw structure corresponding to the outer surface of the microwave heating unit and the inner surface of the dielectric heating unit, respectively. Preferably, the inner lid does not rotate with the microwave heating section.

As can be seen from the above description, in the present invention, in order to utilize a composite heating method utilizing microwaves and electromagnetic energy, the mold used for the method uses a plastic material in which a part thereof has microwave transparency, and the others. Since the structural part of is made of metal material as before, it is durable. Further, in the present invention, since dielectric heating is used, its heat conversion efficiency and heating rate are superior to those of ordinary infrared heating or electric heating tube heating, and energy saving, foam molding under normal pressure or reduced pressure environment can be performed. Can be achieved.

In the conventional heat foaming method, the filling of the material is not tight, and each molecule of the foaming material absorbs the heat source individually. Therefore, the heat conduction efficiency is low, the heat uniformity is insufficient, and the foam molding effect is likely to be lowered due to the insufficient heat uniformity and heat conductivity. In the present invention, compound heating using microwaves and electromagnetic energy (hereinafter abbreviated as composite heating) is used, and by using a mold having a special structure, the internal temperature of the mold can be quickly raised. It is possible to effectively improve the thermal uniformity and improve the problem of the conventional microwave heating non-uniformity. In addition, the conventional heating methods such as hot air, infrared rays, and electric heating tubes can be improved to reduce heat loss and energy consumption and improve thermal uniformity. Since the heat change rate of the electromagnetic energy is higher than that of other methods, the rate of temperature rise is faster than that of the conventional method using a single heating source (for example, microwave, electric heating tube, hot air, etc.). Therefore, it is not necessary to replace the conventional physical or chemical foam molding and separately purchase equipment such as press foam, injection foam, steam press molding (for example, styrofoam, foam bead molding, etc.), extrusion molding, and the like. According to the process and mold of the present invention, a foam such as a physical foam material molded product or a chemical foam material molded product can be produced, and separately mechanical equipment such as a hot extruder, an injection molding machine, or a steam press molding machine can be manufactured. No need to buy. Therefore, it can be easily applied to the machines of each manufacturer, and it is not necessary to spend a high installation cost.

The present invention can achieve weight reduction of plastics by molding physical or chemical foaming materials. Also, according to the mold having a screw that rotates downward, the height of the mold can be adjusted. According to the screwing design of the mold, the contact area between the particles can be improved, and energy consumption and molding time can be reduced. Therefore, the foam molded product can be produced under normal pressure or reduced pressure environment. The method of the present invention can be applied to chemical foaming or physical foaming. According to the composite heating method using microwaves and electromagnetic energy, in the case of a chemical foaming agent, foaming is more stable and uniform, and the strength of the melt is increased by a cross-linking agent, and crystalline and non-crystalline materials are used. Foaming uniformity can be improved. Therefore, problems such as bubbles of the crystalline material being broken or poor moldability can be solved. In the case of a physical foaming material, it is not necessary to add a cross-linking agent, and the foam can be formed into a foam by composite heating. Unlike chemical foams, physical foams are environmentally friendly materials that can be recycled after disposal.

It is a flowchart of 1st Example of this invention. It is a schematic diagram of the 1st Example of the type of this invention. It is a schematic diagram of the 2nd Example of the type of this invention.

This will be described with reference to FIG. The first embodiment of the microwave dielectric heating type foam molding method of the present invention has the following steps 1 to 3.
Step 1: Put the foam material in the mold 10. The mold 10 has a microwave transmitting portion 11 and a dielectric heating portion 13 capable of forming a closed receiving space in the mold 10 by screwing surfaces facing each other.
Step 2: Under normal pressure or reduced pressure environment, microwave W and electromagnetic energy E are simultaneously applied to the mold 10. Preferably, the microwave W is applied to the microwave transmitting unit 11, and the electromagnetic energy E is applied to the dielectric heating unit 13.
Step 3: The foam material is molded into a foam molded product by the microwave W and the electromagnetic energy E.

The frequency of the microwave W is preferably in the range of 100 MHz to 3000 GHz, more preferably in the range of 300 MHz to 3000 GHz. The power of the electromagnetic energy E is preferably in the range of 1 W to 2000 KW, and is determined by the foamed state of the foamed molded product molded by the microwave W and the electromagnetic energy E.

This will be described with reference to FIG. The microwave transmitting portion 11 of the mold 10 of the present invention corresponding to the above method is preferably made of plastic, and the dielectric heating portion 13 is preferably made of metal. In the first embodiment of the mold 10, the microwave transmitting portion 11 and the dielectric heating portion 13 are formed in a structure that can be screwed into each other. Preferably, the bottom portion of the microwave transmitting portion 11 projects outward and is screwed into the inner recess of the dielectric heating portion 13 to form the receiving space. This will be described with reference to FIG. In the second embodiment of the mold 10, the bottom portion of the microwave transmitting portion 11 is flat without protruding outward, and the mold 10 further has an inner lid 12. The inner lid 12 projects outward corresponding to the inner recess of the dielectric heating unit 13. The inner lid 12 and the dielectric heating portion 13 are screwed together to form the receiving space. The foaming material is pressed and fixed by the protruding portion of the microwave transmitting portion 11 placed in the receiving space formed by screwing the microwave transmitting portion 11 and the dielectric heating portion 13, and is aligned with the dielectric heating metal portion. Can be heated uniformly. By applying a pneumatic, electric or hydraulic mechanical external force, the microwave transmitting portion 11 or the inner lid 12 may be closely aligned with the dielectric heating portion 13.

Further, in the third embodiment of the mold 10 of the present invention, by having screw structures (111, 131) corresponding to the outer surface of the microwave transmitting portion 11 and the inner surface of the dielectric heating portion 13, respectively, the above. The height of the structure in which the microwave transmitting portion 11 and the dielectric heating portion 13 are combined can be adjusted. Thereby, the foam material can be molded into different molded bodies, for example, those having different thicknesses of the foamed molded products without preparing another mold. By pressing the microwave transmitting portion 11 against the foaming material, more stable and uniform molding can be performed.

Further, in the third embodiment of the present invention, when the outer surface of the microwave transmitting portion 11 and the inner surface of the dielectric heating portion 13 have screw structures (111, 131) corresponding to each of the outer surface, preferably, further in the above. The lid 12 is used. If the inner lid 12 is installed in the dielectric heating unit 13, it will not rotate in conjunction with the microwave transmission unit 11. Therefore, it can be formed into a non-circular or other asymmetric structure. The heating uniformity and the molding effect can be adjusted by the degree of downward rotation of the microwave transmitting portion 11.

Further, the dielectric heating unit 13 of the present invention may be provided with a temperature monitoring device that immediately monitors the heating temperature.

The screwable structure of the microwave transmitting portion 11 of the mold 10 and the dielectric heating portion 13 includes CNC processing molding, laser processing molding, casting molding, press processing molding, sand mold casting molding, overmolding molding, and rapid prototyping. It can be manufactured by processing methods such as typing, hot extrusion molding, injection molding, or 3D print molding. The screwable structure can directly or indirectly combine the microwave transmitting portion 11 of the mold 10 and the dielectric heating portion 13. Direct combination means that the microwave transmitting portion 11 (also referred to as an upper lid), the inner lid, or the dielectric heating portion 13 (also referred to as a lower lid) is made uneven by the processing molding technique, and the screwed structure is used. Then, the foam material is formed into a foam. Indirectly combining means that the mold 10 and the unevenness are indirectly combined, and the uneven structure and the foaming material are formed into the foam by a composite heating method using microwaves and electromagnetic energy. Insert molding).

Further, the foaming material of the present invention corresponding to the above method is basically classified into three types. The first type is a foaming material that is in a non-foamed state before being placed in the mold 10. The second type is a foaming material that is in an incompletely foamed state or a semi-foamed state before being placed in the mold 10. The third type is a foaming material that is in a foamed state before being placed in the mold 10. The non-foamed state is a state in which the foaming material does not foam in the mixing step before foaming by microwave / electromagnetic energy. The incompletely foamed state or the semi-foamed state is a state in which the foaming material is foamed in the mixing step before the foaming by microwave / electromagnetic energy, but the foaming is incomplete (semi-foamed). An example of this is the case where the foaming agent is incompletely reacted, or when two or more foaming agents having different foaming temperatures are added, the foaming material becomes a small granular semi-foamed state. The foamed state is a state in which the foamed material has already been foamed before being foam-molded by microwave / electromagnetic energy. As an example, a high-pressure fluid is used as a physical foaming agent, and a foam material is produced by techniques such as granulation / plate making by continuous melt extrusion, high-pressure fluid impregnation, dissolution equilibrium, primary heat foaming, secondary heat foaming, and pressure treatment. It is preferable to foam with a supercritical fluid to form foam beads, or to foam thermoplastic polyurethane (E-TPU). Preferred states of the foamed state include beads, plates, strips, stars, or irregular forms.

The foam molded product molded by the microwave dielectric heating type foam molding method of the present invention is divided into a continuous foam structure and a discontinuous foam structure. Regarding the continuous foaming structure, the foaming structure of the foamed molded product obtained by putting the foaming material in an unfoamed state into the mold 10 and foaming the foamed material is a continuous foaming structure. Regarding the discontinuous foam structure, the foamed material in the incompletely foamed state / semi-foamed state and the completely foamed state is used to form the foamed molded product by the microwave electromagnetic energy foam molding method of the present invention, and further incompletely foamed. The foamed molded product is obtained by foam-molding the foamed material in the state again or adhering the foamed material in the foamed state, but it is discontinuous because it is bonded between the foamed structures of the foamed molded product. It has a foamed structure.

Further, the foaming material contains 99.98 parts or less (preferably 99 parts or less) of the thermoplastic material, 0.1 to 30 parts of the foaming agent, and 0.01 to 20 parts of the microwave and / or electromagnetic energy absorber. Including.

Preferably, the foaming agent further comprises 0.1-10 parts of a cross-linking agent, 0.01-20 parts of a microwave absorption accelerator, and / or 0.01-20 parts of a functional additive. In that case, the amount of the thermoplastic plastic material is 99.77 parts or less (preferably 99 parts or less), and the contents of the foaming agent and the microwave and / or electromagnetic energy absorber are the same as described above. The part described in the ratio indicates wt%.

Examples of the thermoplastic plastic material include crystalline or non-crystalline liquid or solid materials and copolymers thereof. Examples of such a material include polyester thermoplastic resin, dynamically crosslinked thermoplastic resin, polystyrene-based resin, polyolefin-based resin, rubber, silicon resin, fluororesin, polycarbonates, and biodegradable resin. Polyethylene (PE), Polyester (PP), Polyvinyl Chloride (PVC), Polystyrene (PS), Acrylonitrile-butadiene-styrene copolymer (ABS), Phenolic resin (PF), Urea resin (UF), Polyvinyl alcohol (PVA) ), Ethethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), nitrile rubber (NBR), olefin-based elastomer (TPO), dynamically cross-linked thermoplastic elastomer (TPV), polyester-based thermoplastic elastomer (TPEE), Ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), polyurethane (PU), polyisocyanurate (PIR), polyamide resin (PA), polyethylene terephthalate (PET), polylactic acid (PLA), hydroxybutyrate-variate Copolymer (PHBV), Polybutylene succinate (PBS), Melamine, Polyester Polyol, such as Polyester Diol, Polycaprolactone (PCL), Lactobacillus-glycolic acid copolymer, Poly 3-Hydroxybutyrate (P3HB), polymethylmethacrylate (PMMA), epoxy resin (Epoxy), polytetramethylene carbonate, liquid silicone rubber, polyethylene terephthalate-1,4-cyclohexanedimethylester (PETG), or terephthalic acid- Examples thereof include 1,4-cyclohexanedimethanol-2,2,4,4-tetramethyl-1,3-cyclobutanediol copolymer (Tritan Polyester).

Examples of the foaming agent include a physical foaming agent, a chemical foaming agent, or a physicochemical composite foaming agent (that is, both a physical foaming agent and a chemical foaming agent are used). The physical foaming agent includes expanded microspheres (foamed microspheres), hollow microspheres (eg, glass hollow microspheres, ceramic hollow microspheres, phenol resin hollow microspheres, etc.), powders (eg, glass fibers, carbon fibers, etc.). Powder), gaseous physical foaming agent, liquid physical foaming agent. Examples of the gaseous physical foaming agent include pentane, hexane, heptane, dichloromethane, dichloroethane, trichloromethane, butane, isoheptane, nitrogen gas, carbon dioxide gas, argon gas, helium gas, oxygen gas, neon gas, air and the like. The liquid physical foaming agent includes aliphatic hydrocarbons, low boiling point (<300 ° C.) alcohols, esters, ethers, ketones, aromatic hydrocarbons, chlorofluorocarbons, hydrocarbons (for example, hydrofluoroolefins), hydrochlorofluorocarbons, and hydrofluorocarbons. , Carbon halide, perfluoropropane, petroleum ether, ethanol, dimethyl ether, diethyl ether, methyl ethyl ether, toluene, acetone, chlorofluoromethane, trifluoromethane, 1,1-difluoroethane, 1,1,1,2-tetrafluoro Examples thereof include ethane, chloromethane, chloroethane, dichloromethane, hypochlorofluorocarbons, cyclohexanes and cyclopentanes. Examples of the chemical foaming agent include an inorganic chemical foaming agent and an organic chemical foaming agent. Examples of the inorganic chemical foaming agent include sodium hydrogen carbonate, sodium carbonate, ammonium carbonate, ammonium hydrogen carbonate, ammonium nitrite, potassium borohydride, sodium borohydride, hydrogen peroxide and the like. The organic chemical effervescent agent includes azodicarbonamide (AC), azobisisobutyronirile (AIBN), diisopropyl azodicarboxylate (Diisopropyl Azodicarboxylate, DIPA), N, N'-dinitro. Amin (N, N'-Ditintroso Pentamethylene Hydrazide, DPT or DNPT), p-Toluene Sulfonyl Hydrazide, TSH, 4,4'~ Oxydibenzenesulfonyl Hydrazide (4,4'-Oxydrazide) OBSH), benzenesulfonyl hydrazide (Bendenesulfonyl Hydrazide, BSH), trihydrazidotriazine (Trit), p-toluenesulfonyl semicarbazide (P-Toluenesulfonyl Azobisisobuty, P-Toluenesulfonyl Semicarbazid, Dimethylvaleronitrile) (2,2'-Azobis (2,4-dimethyl) valeronitrile, ABVN), hydrazides sulfate, azonitriles, azodicarboxylic acid derivatives, benzenesulfonyl hydrazide compounds, nitroso compounds, diazobenzene compounds, urea and other compounds , And their copolymers.

As the cross-linking agent, one kind or two or more kinds of cross-linking agents may be added. The types of the cross-linking agent are dicumyl peroxide (DCP), 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane (2,5-dimethyl-2,5-di (tert-)). butyl peroxide (BPO), trade name L-101), benzoyl peroxide (BPO), di-tert-butyl peroxide, TBP, 2,5-dimethyl-2-hydroxy-5- tert-butylperoxy-3-hexine (2,5-dimethyl-2-hydroxy-5-tert-butyl peroxide, trade name OP-2), triallyl isocyanurate (TAIC), di- tert-butyl peroxide (DTBP), acrylic acid (AA), diacetyl peroxide, tert-butyl peroxypivalate, tert-butyl peroxide, tert-butyl peroxide, tert-butyl peroxide, tert-butyl peroxide, AA. Isopropylbenzene (tert-butyl peroxide), 1,1-di (tert-butylperoxy) -3,3,5-trimethylcyclohexane (1,1-di- (tert-butyl peroxide) -3,3,5-trimethylcyclohexane) ), 2,5-Dimethyl-2,5-di (tert-butylperoxy) hexane (2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane), butyl-4,4-bis (tert) -Butyldioxy) Valerate (butyl-4,4-bis (tert-butyldioxy) peroxide), bis (2,4-dichlorobenzoyl) peroxide (bis (2,4-dichlorobenzoyl) peroxide), bis (4-methylbenzoyl) peroxide (Bis (4-methylbenzoyl) peroxide), 1,4-di (2-tert-butylperoxyisopropyl) benzene (1,4-di- (2-tert-butylperoxyisopropyl) be nzene), tert-butyl peroxybenzoate, tert-butyl-3,5,5-trimethylperoxyhexanoate (tert-butyl-3,5,5-trimethylperoxyhexanoate), tert-butylperoxy-2 -Ethylhexyl carbonate (tert-butylperoxy-2-ethylhexyl carbide), trioxacycloheptane compound, 3,3,5,7,7-pentamethyl-1,2,4-trioxepan (3,3,5,7,7-) pentamethyl-1,2,4-trioxepane), lauroyl peroxide, di (4-tert-butylcyclohexyl) peroxydicarbonate (di (4-tert-butylcyclohexyl) peroxydicyclodicarbonate, dicetylperoxydicarbonate). ), Dimyristyl peroxydicarbonate, tert-amyl peroxypivalate, di-3-methoxybutyl ester peroxydicarbonate, di-3-methoxybutylibiyl peroxide. Peroxide), tert-butyl peroxyneodecanoate, tert-butyl peroxyneoheptanoate, di (3,5,5-trimethylhexanoyl) peroxide (3,5,5-trimethylhexanoyl) , 5,5-trimethylhexanoyl) peroxide), 1,1,3,3-tetramethylbutyl peroxyneodecanoeto (1,1,3,3-tetramethylbutyl peroxide peroxide), cumemperoxyneodecanoate. Di (2-ethylhexyl) peroxydicarbonate (di (2-ethylhexyl) peroxide), bis (a) Sopropyl) peroxydicarbonate (bis (isopropyl) peroxide peroxide), 1,1-di (tert-butylperoxy) -3,3,5-trimethylcyclohexane (1,1-di (tert-butylperoxy) -3,3,5 -Trimethylcyclohexane), 2,2'-azobis (2-methylbutyronitrile) (2,2'-azobis (2-methylbutyrontile)), decanoyl peroxide, 1,3-bis (tert-butylperoxy) Isopropyl) benzene (1,3-bis (tert-butylperoxy-isopropyl) bendene), 1,4-bis (tert-butylperoxyisopropyl) benzene (1,4-bis (tert-butylperoxy-isopropyl) bendene), 2,5- Dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane (2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane), tert-amylperoxy-2-ethylhexyl carbonate (tert-amylperoxy-) 2-ethylhexyl peroxide), tert-butyl hydroperoxide, 3,5-diisopropylbenzene hydroperoxide (3,5-diisopropylbendene peroxide peroxide), maleic anhydride (melaic peroxide), male peroxide peroxide (melaic peroxide) Can be mentioned.

The incompletely foamed / semi-foamed or fully foamed physical or chemically foamed material of the present invention can be used alone without the addition of the cross-linking agent, or the chemical foaming agent, physical foaming agent, foamed microspheres. Alternatively, it can be used in combination with foam beads and can be further formed into a discontinuous foam structure or a continuous foam structure by microwave and electromagnetic energy composite heating.

The microwave and / or electromagnetic energy absorber is used so that the foam material has the ability to absorb microwave and / or electromagnetic energy, and one or a combination of the following materials can be used. The material includes a microwave absorbing material and an electromagnetic energy absorbing heat conductive material. Examples of the microwave absorbing material include nitrides, oxides, carbides, graphene, glass fibers, carbon fibers, cellulose nanocrystals and the like. Examples of the nitride include boron nitride, silicon nitride, vanadium nitride, titanium nitride, gallium nitride, and aluminum nitride. Examples of the oxide include aluminum oxide, magnesium oxide, zinc oxide, zirconium oxide, iron oxide, silicon oxide, titanium oxide and copper oxide. Examples of the carbide include silicon carbide, vanadium carbide, titanium carbide, boron carbide, niobium carbide, molybdenum carbide, tantalum carbide, chromium carbide, hafnium carbide, zirconium carbide, tungsten carbide, carbon fiber, and carbon nanotube. The electromagnetic energy absorbing thermal conductive material includes nanoelement powder, for example, nanographite powder, nanomolybdenum powder, nanosilicon powder, nanotitanium powder, nanocobalt powder, nanobismus powder, nanogold powder, nanosilver powder, nanocopper powder, nano. Examples thereof include aluminum powder, nanozinc powder, nanotin powder, nanonickel powder, nanoiron powder, and nanotungsten powder.

The microwave absorption accelerator is used to promote microwave heating uniformity by externally adding to the foam material so as to promote microwave absorption (the thermoplastic plastic material, a foaming agent (microsphere)). , Foaming agents), microwave / electromagnetic energy absorbers, cross-linking agents, and functional additives belong to the internal components). The microwave absorption accelerator can be preferably added to the foaming material in the incompletely foamed state / semi-foamed state or the completely foamed state and adhered to the surface of the foaming material to promote the microwave absorption effect. Next, the reaction mechanism of microwave irradiation will be described. Simply put, in dipole polarization and ionic conduction, the action of microwave fields generates heat because the dipoles or ions do not match the molecular motion or dielectric loss due to the vibrational conversion of the electric field (or magnetic field). Therefore, ionizable materials such as surfactants or salts have the effect of improving heating efficiency and thermal conductivity by the action of a microwave field or an electromagnetic energy field. From a microscopic point of view, the ionizable material is adsorbed on the foaming material, and by removing the air adsorbed on the surface of the foaming material, the gap created between the foaming material particles by the air can be reduced. Therefore, the adhesion and the bonding state of the foamed structure can be improved, and the thermal conductivity and the heating rate can be improved. The microwave absorption accelerator of the present invention is preferably a polar liquid or a liquid containing a polar substance, or an ionizable / ionizable liquid, for example, water, a surfactant, salts, organic acids, organic alcohols and the like. Can be used alone or in combination with the above materials. The surfactant includes a cationic surfactant, an anionic surfactant, an amphoteric surfactant, and a nonionic surfactant (of which the nonionic surfactant does not ionize, but the ionizing material is a foaming material. Has the effect of stably adsorbing). Since the surfactant has a low melting point, it has the effect of absorbing microwave / electromagnetic energy and rapidly heating the surface of the foaming material to adhere the foaming materials to each other. The organic acid and the organic alcohol preferably have 6 or less carbon chains. Examples of the salts include compounds having a metal ion, an ammonium ion, an acid group ion, and a non-metal ion bond. The microwave absorption accelerator has good microwave absorption and excellent thermal conductivity. A polar liquid having a high boiling point or a low boiling point can be selected depending on the process temperature. If the process temperature is high, use a polar liquid with a high boiling point. On the contrary, when the process temperature is low, a polar liquid having a low boiling point is used. The microwave absorption accelerator improves the problem that the foam beads having a high melting point cannot be molded stably, improves the adhesive force between the foam beads, and avoids problems such as bursting or insufficient strength.

The functional additive is used to have functionality, and is used as a plasticizer, lubricant, surfactant, bubble conditioner, flame retardant, coupling agent, enhancer, antioxidant, antistatic agent, heat stabilizer. , Light stabilizers, colorants, processing aids, impact resistance improvers, inorganic powders, filler powders. The plasticizer includes benzoic acid esters (for example, methyl benzoate, ethyl benzoate, dipropylene glycol dibenzoate and derivatives thereof), and ester compounds (for example, triethyl citrate, trimethyl citrate, acetyltriethyl citrate ester and derivatives thereof). , Ether compounds (eg, adipic acid ether ester, ethylene glycol butyl ether ester and derivatives thereof), polycaprolactone compounds (eg, polycaprolactone diol and derivatives thereof) or carbonate compounds (eg, dimethyl carbonate, diphenyl carbonate and derivatives thereof). Examples of the surfactant include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. Examples of the bubble adjusting agent include zinc borate, borax, phosphoric acid-based nucleating agent, phenol-based nucleating agent, amine-based nucleating agent, and polyfluoroethylene-based resin powder. Examples of the inorganic powder include talc powder, calcium carbonate, kaolin, zeolite, mica powder, and sodium thiosulfate. Examples of the filler powder include organic microspheres, inorganic microspheres, metal particles, and metal oxide microspheres. The filler powder has the effect of reducing the amount of plastic and the weight of the foam molded product of the present invention, and the physical foam molded product. Strength, such as abrasion resistance, can be improved. Among them, the microsphere may be a solid microsphere or a hollow microsphere (having a weight reduction effect). The organic microspheres include polyester microspheres, polyvinylidene chloride microspheres, acrylic resin microspheres, phenol resin microspheres, polylactic acid microspheres, polystyrene microspheres, epoxy resin microspheres, polyaniline microspheres, polyamide microspheres, and melamine /. Formaldehyde microspheres can be mentioned. Examples of the inorganic microspheres include glass microspheres, ceramic microspheres, silicon dioxide microspheres, carbon microspheres, calcium carbonate microspheres, and graphene microspheres. Examples of the metal particles include particles such as magnesium, aluminum, zirconium, calcium, titanium, vanadium, chromium, cobalt, nickel, copper, germanium, molybdenum, silver, indium, tin, tungsten, iridium, platinum, iron, and gold. Be done. Examples of the metal oxide microsphere include aluminum oxide microsphere. The microspheres can be used alone or in combination. Further, the surface of the microsphere may be surface-treated to improve the uniformity of mixing. Examples of the surface treatment include a treatment of lowering the surface tension by using a polysiloxane compound or a fluorine-containing compound.

Table 1 shows two embodiments of the present invention using EVA or PE as the thermoplastic material.

The present invention is not limited to the above examples. Equal changes and improvements made in the spirit of the invention are all within the scope of the invention.

Type 10 11 Microwave transmission part 111 Male thread structure of microwave transmission part 13 Dielectric heating part 131 Female screw structure of dielectric heating part W Microwave E Electromagnetic energy

Claims (10)

The process of putting the foam material into the mold and
A step of simultaneously applying microwaves and electromagnetic energy to the mold under normal pressure or reduced pressure environment,
It has a step of foaming the foaming material into a foamed molded product having a continuously foamed structure or a discontinuous foamed structure by the microwave and the electromagnetic energy.
The mold has a microwave transmitting portion and a dielectric heating portion capable of forming a closed receiving space in the mold by screwing surfaces facing each other.
A microwave dielectric heating type foam molding method, characterized in that the microwave is applied to the microwave transmitting portion and the electromagnetic energy is applied to the dielectric heating portion. The microwave dielectric heating type foam molding method according to claim 1, wherein the foamed material is in an unfoamed state, a semi-foamed state, or a foamed state when placed in the mold. The microwave dielectric heating type foam molding method according to claim 2, wherein the foamed state of the foam material is in a bead shape, a plate shape, a strip shape, a star shape, or an irregular shape. The unfoamed state of the foaming material has a continuously foamed structure.
The microwave dielectric heating type foam molding method according to claim 3, wherein the foamed state or the semi-foamed state has a discontinuous foamed structure. By applying the microwave and the electromagnetic energy to the microwave transmitting portion of the mold and further applying a pneumatic, electric or hydraulic mechanical external force, the microwave transmitting portion is heated by the dielectric heating unit. The microwave dielectric heating type foam molding method according to claim 2, which is characterized by being closely aligned with the above. A microwave transmission part whose bottom protrudes outward, and
A foam molding mold for microwave dielectric heating, characterized in that the top portion is recessed inward and has a dielectric heating portion capable of forming a receiving space by screwing with the microwave transmitting portion. It is characterized by further having an inner lid provided between the microwave transmitting portion and the dielectric heating portion, the bottom portion of which protrudes outward, and which can be screwed with the top portion of the dielectric heating portion to form the receiving space. , The foam molding mold for microwave dielectric heating according to claim 6. The foam molding mold for microwave dielectric heating according to claim 6, wherein the microwave heating unit is made of plastic and the dielectric heating unit is made of metal. By having a screw structure corresponding to the outer surface of the microwave heating unit and the inner surface of the dielectric heating unit, the microwave heating unit is rotated and screwed to the dielectric heating unit. The foam molding mold for microwave dielectric heating according to claim 6. The foam molding mold for microwave dielectric heating according to claim 6, wherein the inner lid does not rotate together with the microwave heating unit.